tableViewController.swift:
import UIKit
import os.log

class TableViewController: UITableViewController {

    //temp list of tasks
    var tasks = [task]()



    override func viewDidLoad() {
        super.viewDidLoad()

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        //self.navigationItem.leftBarButtonItem = self.editButtonItem

        //giving some default values in the cell
        //tasks += ["something"]

        loadSampleTasks()

    }

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return tasks.count
    }



    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "simpleCell", for: indexPath)

        // Configure the cell...
        let row = indexPath.row

        cell.textLabel?.text = tasks[row].title

        //makes the cell background gray if its done
        if tasks[row].done {
            cell.backgroundColor = UIColor.lightGray
        }



        return cell
    }


    // Override to support conditional editing of the table view.
    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }



    // Override to support editing the table view.
    override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            // Delete the row from the data source
            tasks.remove(at: indexPath.row)
            tableView.deleteRows(at: [indexPath], with: .fade)
        } else if editingStyle == .insert {
            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
        }
    }

    //leading swipe for editing code
    override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {

        let edit = UIContextualAction(style: .normal, title: "Edit") { (contextualAction, view, actionPerformed: (Bool) -> ()) in
            self.performSegue(withIdentifier: "showDetail", sender: UITableViewCell())
            actionPerformed(true)

        }

        return UISwipeActionsConfiguration(actions: [edit])
    }


    /*
    // Override to support rearranging the table view.
    override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to: IndexPath) {

    }
    */

    /*
    // Override to support conditional rearranging of the table view.
    override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the item to be re-orderable.
        return true
    }
    */



    // MARK: -Action
    @IBAction func unwindToTaskList(sender: UIStoryboardSegue) {
        if let sourceViewController = sender.source as? ViewController, let task = sourceViewController.Task {

            if let selectedIndexPath = tableView.indexPathForSelectedRow {
                // Update an existing task.
                tasks[selectedIndexPath.row] = task
                tableView.reloadRows(at: [selectedIndexPath], with: .none)
            }else {
                // Add a new meal.
                let newIndexPath = IndexPath(row: tasks.count, section: 0)

                tasks.append(task)
                tableView.insertRows(at: [newIndexPath], with: .automatic)
            }
        }
    }


    // MARK: - Navigation


    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        // Get the new view controller using segue.destination.
        // Pass the selected object to the new view controller.
        super.prepare(for: segue, sender: sender)

        switch(segue.identifier ?? "") {

            case "addItem":
            os_log("Adding a new task.", log: OSLog.default, type: .debug)

            case "showDetail":
            guard let ViewController = segue.destination as? ViewController else {
                fatalError("Unexpected destination: \(segue.destination)")
            }

            guard let selectedTaskCell = sender as? taskCellTableViewCell else {
                fatalError("Unexpected sender: \(sender)")
            }

            guard let indexPath = tableView.indexPath(for: selectedTaskCell) else {
                fatalError("The selected cell is not being displayed by the table")
            }

            let selectedTask = tasks[indexPath.row]
            ViewController.Task = selectedTask

            default:
            fatalError("Unexpected Segue Identifier; \(segue.identifier)")

        }
    }

    private func loadSampleTasks(){

               let formatter = DateFormatter()
               formatter.dateFormat = "MM/dd/yyyy"
               let date = formatter.date(from: "02/28/2020")

        guard let task1 = task(title: "call mom", done: false, date: date! )else{ fatalError("fuck you")}

        tasks += [task1]
    }

}

viewController aka the detail screen:
import UIKit
import os.log

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet weak var taskTitleTextField: UITextField!
    @IBOutlet weak var taskLabel: UILabel!
    @IBOutlet weak var saveButton: UIBarButtonItem!

    @IBOutlet weak var doneSwitch: UISwitch!

    //code for the done button
    @IBAction func doneButton(_ sender: UIBarButtonItem){

        let isPresentingInAddMealMode = presentingViewController is UINavigationController

        if isPresentingInAddMealMode {
        dismiss(animated: true, completion: nil)
        }else if let owningNavigationController = navigationController{
            owningNavigationController.popViewController(animated: true)
        }else {
            fatalError("The MealViewController is not inside a navigation controller.")
        }
    }


    //gobal datePicker and toolbar for the date
    var toolBar = UIToolbar()
    var datePicker  = UIDatePicker()

    var dateString : String = "" //holds the dateString for the button title

    @IBOutlet weak var titleHolder: UIButton!

    //shows the date picker when the button is pushed
    @IBAction func datePickerButton(_ sender: UIButton) {

       datePicker = UIDatePicker.init()
       datePicker.backgroundColor = UIColor.white

       datePicker.autoresizingMask = .flexibleWidth
       datePicker.datePickerMode = .date

       datePicker.addTarget(self, action: #selector(self.dateChanged(_:)), for: .valueChanged)
       datePicker.frame = CGRect(x: 0.0, y: UIScreen.main.bounds.size.height - 300, width: UIScreen.main.bounds.size.width, height: 300)
       self.view.addSubview(datePicker)

       toolBar = UIToolbar(frame: CGRect(x: 0, y: UIScreen.main.bounds.size.height - 300, width: UIScreen.main.bounds.size.width, height: 50))
       toolBar.isTranslucent = true

       toolBar.items = [UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil), UIBarButtonItem(title: "Done", style: .done, target: self, action: #selector(self.onDoneButtonClick))]

       toolBar.sizeToFit()
       self.view.addSubview(toolBar)

        //sets the button to the date
        //sender.setTitle(dateString, for: .normal)
    }

    //updates the due date
    @objc func dateChanged(_ sender: UIDatePicker?) {

        if let date = sender?.date {
            Task?.date = date
            dateString = dateToString(date: date)
        }
    }

    @objc func onDoneButtonClick() {
        toolBar.removeFromSuperview()
        datePicker.removeFromSuperview()
        titleHolder.setTitle(dateString, for: .normal)
    }

    //the task that gets sent back after saving
    var Task: task?

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        // Handle the text field’s user input through delegate callbacks.
        taskTitleTextField.delegate = self

        // Set up views if editing an existing task.
        if let Task = Task {
            navigationItem.title = Task.title
            taskTitleTextField.text = Task.title
            taskLabel.text = Task.title
            doneSwitch.isOn = Task.done
            titleHolder.setTitle(dateToString(date: Task.date), for: .normal)

        }

        // Enable the Save button only if the text field has a valid task title.
        updateSaveButtonState()
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        //hides the keyboard and stops the textField from being the first responder
        textField.resignFirstResponder()
        return true
    }

    func textFieldDidEndEditing(_ textField: UITextField) {

        taskLabel.text = textField.text

        updateSaveButtonState()
        navigationItem.title = textField.text
    }

    // This method lets you configure a view controller before it's presented.
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        super.prepare(for: segue, sender: sender)

        guard let button = sender as? UIBarButtonItem, button === saveButton else {
            os_log("the save button was not pressed to get here, stopping", log: OSLog.default, type: .debug)
            return
        }

        let title = taskTitleTextField.text ?? ""
        let date = Task?.date ?? Date()
        let done = doneSwitch.isOn

        Task = task(title: title, done: done, date: date)

    }

    //MARK: Save Button
    //ensures new information was given when saving
    func textFieldDidBeginEditing(_ textField: UITextField) {
        // Disable the Save button while editing.
        saveButton.isEnabled = false
    }

    private func updateSaveButtonState() {
        // Disable the Save button if the text field is empty.
        let text = taskTitleTextField.text ?? ""
        saveButton.isEnabled = !text.isEmpty
    }

    //func for converting a date to a string
    func dateToString(date: Date) -> String{
        let formatter = DateFormatter()
        formatter.dateFormat = "MM/dd/yyyy"

        return formatter.string(from: date)
    }
}

tableViewCell.swift:
import UIKit

class taskCellTableViewCell: UITableViewCell {

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

}